1. Field of the Invention
The present invention relates to an ultrasonic endoscope, which uses ultrasonic waves for the diagnosis of a diseased tissue. Especially, the present invention relates to a construction of the portion of the point in the endoscope.
2. Description of the Related Art
In the ultrasonic endoscope, an ultrasonic probe having ultrasonic wave vibrators is provided at the distal end of the endoscope. The ultrasonic probe sends ultrasonic waves and receives echoes of the sent ultrasonic waves.
For the scanning method, a radial scanning or a linear scanning is used. For example, when diagnosing an organ (body-cavity), into which the ultrasonic endoscope cannot be inserted, the radial scanning is performed. The endoscope is inserted toward an organ adjacent to the observed organ, ultrasonic waves are sent radially from the ultrasonic probe. Conventionally, a mechanical-type radial scanning is applied, where a series of ultrasonic wave vibrators is aligned along an axis of the probe and revolves on the axis to send the ultrasonic waves radially.
However, in the case of the mechanical type radial scanning, a color-image, partially colored by Red (R), G (Green), B(Blue), which is effective for diagnosis of the diseased areas, cannot be displayed on the monitor.
Further, while manipulating the bending portion, various forces act on signal transmitting members for transmitting signals associated with the ultrasonic waves and the echoes. Therefore, a greater durability for the bending motion is required for the signal transmitting members provided in the distal end of the endoscope.
Therefore, an object of the present invention is to provide an ultrasonic endoscope that is capable of obtaining an observed-image for diagnosis, and further that is durable in its bending motion.
An ultrasonic endoscope according to the present invention is an endoscope for performing electronic radial scanning. A bending portion formed in a tube is connected to the point of a flexible tube, which is inserted in a body, or organ. The flexible tube is normally connected to a manipulator portion of the endoscope, and an operator, such as a doctor, bends the bending portion by manipulating a manipulating knob, which is operatively connected to the bending portion. Namely, the bending portion bends by remote control.
An ultrasonic probe for the electronic radial scanning is operatively connected to the bending portion. For example, a solid point-base portion is connected to the bending portion and the ultrasonic endoscope is attached to the point-base portion.
The ultrasonic probe has a plurality of ultrasonic wave vibrators, which are arranged circumferentially to perform the electronic radial scanning. The plurality of ultrasonic wave vibrators send ultrasonic waves radially around a center axis of the ultrasonic probe and receive echoes of the ultrasonic waves.
According to the present invention, a flexible circuit board is provided in the endoscope. The flexible circuit board transmits signals associated with ultrasonic waves and echoes, so that an ultrasonic-image, representing a section-image in the body, is obtained at the ultrasonic wave diagnosis apparatus. As electronic scanning (not mechanical scanning) is performed, an ultrasonic color-image is obtained as required by simultaneously sending multiple ultrasonic waves, each frequency of which is different, or an ultrasonic pulse-width image is obtained by coloring in accordance with contrast of the echoes. These images cannot be obtained by mechanical radial scanning.
In the bending portion, the flexible circuit board is constructed of a plurality of flexible circuit board strips so as to allow a bending motion, namely, to be capable of withstanding the bending motion. The plurality of flexible circuit board strips extends along a central axis of the bending portion (herein, represented by xe2x80x9ca first central axisxe2x80x9d). The signal-transmitting member in the bending portion is composed of a plurality of flexible circuit board strips, which prevent snapping while the bending portion is manipulated. The plurality of flexible circuit board strips enables the circumferential arrangement of the ultrasonic wave vibrators, namely, the electronic radial scanning. Note that, the width of each flexible circuit board strips is defined in accordance with a radius of the bending portion.
An ultrasonic wave coaxial cable, which is provided in the flexible tube and which transmits the signals associated with the ultrasonic waves and echoes, is formed by bundling a plurality of ultrasonic wave coaxial signal lines. Part of the ultrasonic wave coaxial signal lines are separate and extend from the ultrasonic wave coaxial cable along a central axis of the flexible tube (herein, represented by xe2x80x9ca second central axisxe2x80x9d). The plurality of ultrasonic wave coaxial signal lines are connected to the plurality of flexible circuit board strips so that the signals associated with the ultrasonic wave and the echoes are transmitted between the ultrasonic wave diagnosis apparatus and the ultrasonic probe.
The plurality of ultrasonic wave coaxial signal lines are flexible and loose in a given range so as to xe2x80x9cacceptxe2x80x9d, or absorb the compressing and extending forces. Note that, the forces operate along the first and second central axes, against the plurality of flexible circuit board strips, the plurality of ultrasonic wave coaxial signal lines, and the ultrasonic wave coaxial cable. While the bending portion is manipulated, the loose coaxial signal lines are flexed and pulled more compared to the flexible circuit board strips when the compressing and expanding forces occur along the first and second central axes. Namely, the unbundled coaxial lines absorb the compressing and extending forces by flexure and extending. Thus, excessive flex and extension do not occur in the circuit board strips while bending the bending portion so that snapping of the printed wiring on the circuit board strips does not occur.
To provide sufficient flexibility for the ultrasonic wave coaxial signal lines, preferably, the length of the given range along the second axis is equal to or more than the length of the plurality of flexible circuit board strips along the first central axis.
As for the total construction of the flexible circuit board, the flexible circuit board strips may be composed of the flexible circuit board strips (pieces), which are connected to the ultrasonic wave vibrators separately. However, to make the flexible circuit board strips stronger than the ultrasonic wave coaxial signal lines with respect to the compressing and expanding forces, preferably, the flexible circuit board is formed by partially cutting a single rectangular flexible circuit board such that the plurality of flexible circuit board strips are formed and then rounding said cut rectangular flexible circuit board so as to form a cylindrical shape.